1. Field of the Invention
The present invention relates to a conveying system that uses a linear motor for conveying works, assembly components, or other articles to be conveyed.
2. Description of the Related Art
Conveying apparatuses have been extensively used that employ rollers or belts to carry works, assembly components, or other articles to be conveyed. Especially in the case of a conveying apparatus that employs a belt, in order to stop only a particular article in transfer at a predetermined position, the article has to be forcibly restrained, inevitably producing friction between the belt and the article. Further, the accuracy of positioning at the stop point is not very high.
In recent years, linear motor type conveying systems have been proposed and used as the conveying systems for clean rooms, nuclear power stations, physical distribution, etc. A linear induction motor is capable of carrying considerably heavy articles and it is therefore being used as a typical motor used for conveyance. The linear induction motors, however, are considered unsuited for applications that require accurate positioning at stop points.
The conventional conveying systems employing belts or rollers have difficulties in the aspect of the control of dust, carrying speed, maintenance, service life, and positioning control. The linear induction motor type is also disadvantageous in positioning control. The linear motors that allow the braking characteristics thereof to be adjusted have been requiring power be fed to a moving unit thereof, so that the moving unit is likely to produce dust.